1. Field of the Invention
This invention relates generally to a device for testing the crushability of materials, and more specifically to a device for measuring the volumetric deformation of a crushable foam under triaxial loading as a function of pressure.
2. Description of the Prior Art
Various devices for testing the deformability or hardness of materials such as soil samples or cigarettes include several shortcomings and drawbacks. For example, some systems use an arrangement where a piston moves inward into a fluid-filled container in order to increase the pressure within the container to thereby crush material such as rock, salt, ice or concrete. In such systems, two main drawbacks exist. First, it may be difficult to maintain enough pressure on the piston external from the fluid-filled chamber in order to increase the amount of pressure within the chamber in a desired fashion. Second, movement of the piston into the fluid-filled chamber undesirably changes the confining pressure within the chamber; under some conditions it may be desirable to maintain a constant pressure within a pressurized chamber.
Other devices for testing the hardness of a cigarette, for example, include the use of pneumatic suction applied to the interior of a cigarette. The volumetric change of the cigarette under the suction is measured. In such systems, the outer diameter of the cigarette is measured before and after the suction is applied. Significant drawbacks in such systems are present because the methodology requires relatively sophisticated and costly equipment that is only usable by skilled personnel under very controlled laboratory conditions. Further, a continuous measurement of deformation is unattainable.
This invention provides a system for measuring the volumetric change or crushability of a crushable foam that overcomes the drawbacks and shortcomings of the prior art just described. Accordingly, it is a primary object of this invention to provide a system for continuously measuring the crushability of a crushable foam under triaxial loading in an efficient, cost-effective manner.